Plans to compress internet (VoIP) phone calls so they use less bandwidth could make them vulnerable to eavesdropping. Most networks are currently safe, but many service providers are due to implement the flawed compression technology.

A team from John Hopkins University in Baltimore, Maryland, US, has shown that simply measuring the size of packets without decoding them can identify whole words and phrases with a high rate of accuracy. A paper on the Johns Hopkins team's work was presented at the 2008 IEEE Symposium on Security and Privacy, in Oakland, California, US, last month.